Journal of Volcanology and Seismology最新文献

{"title":"Volcanic Rock Structures as Indicators of Dangerous Environmental Impact: The Late Cenozoic Volcanics in the Caucasus","authors":"A. M. Kurchavov","doi":"10.1134/S0742046322700038","DOIUrl":"10.1134/S0742046322700038","url":null,"abstract":"<p>The structure features of lavas and ignimbrites indicate a high role of volatiles in their formation and a rapid release of volatiles from cooling melt. This poses a high risk for the environment. For this reason it is important to study the structures of resulting volcanic rocks for predicting the degree of hazard in the event of a future resumption of volcanic activity.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"17 1","pages":"37 - 41"},"PeriodicalIF":0.7,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4783473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Zeolite Mineralization in Mudstones of the East Pauzhetka Thermal Field As an Indicator of the Discharge of Alkaline Fluids in a Present-Day Hydrothermal System, Southern Kamchatka","authors":"E. I. Sandimirova,&nbsp;S. N. Rychagov,&nbsp;A. V. Sergeeva,&nbsp;V. M. Chubarov","doi":"10.1134/S0742046322060070","DOIUrl":"10.1134/S0742046322060070","url":null,"abstract":"<p>The argillized deposits of the East Pauzhetka thermal field in the Pauzhetka hydrothermal system were found to contain a zone of intensive zeolitization which consists of medium to high silica calcium zeolite varieties, namely, laumontite, mordenite, heulandite-Ca, and stilbite-Ca. Of all these, stilbite-Ca has the highest abundance. The zeolites can be identified well enough based both on the relationship between Si and Al, which are part of the zeolite framework, and on the concentrations of non-framework cations (Ca, Mg, Na, K, Sr, and Ba). Zeolites are mostly formed in the lower horizons of hydrothermal clays and in the underlying argillized andesites, as deep alkaline chloride-sodium hydrothermal fluids are discharged and are mixed with condensates of acid (up to neutral) vapor. The resulting sequence of zeolite generation in the shallow zone where alkaline solutions are discharged reflects, to a certain degree, a change of zeolite facies in the deeper horizons of the system: from medium-silica laumontite to high silica stilbite-Ca. We have thereby a general inference as to the regressive directivity of hydrothermal metamorphic processes in the Pauzhetka system structure, from medium-temperature propylites generated during the paleo phase to the present-day low-temperature mudstones.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"432 - 450"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4640094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated Geological and Geophysical Surveys of the Lisyansky Submarine Volcano, Kuril Island Arc","authors":"Yu. I. Blokh,&nbsp;V. I. Bondarenko,&nbsp;A. S. Dolgal,&nbsp;P. N. Novikova,&nbsp;V. V. Petrova,&nbsp;O. V. Pilipenko,&nbsp;V. A. Rashidov,&nbsp;A. A. Trusov","doi":"10.1134/S0742046322050037","DOIUrl":"10.1134/S0742046322050037","url":null,"abstract":"<p>Integrated geological and geophysical surveys of the Lisyansky submarine volcano in the Simushir volcanic zone of the Kuril island arc showed that the lower horizons of this volcanic edifice are composed of pyroxene–hornblende–plagioclase porphyritic basalts, while the upper horizons consist of pyroxene–plagioclase andesites and basaltic andesites. It was for the first time in the study of this volcano that distinct mineralogical signs of fumarolic hydrothermal activity have been identified. High values of magnetization in basalts are due to considerable concentrations of titanomagnetite grains which have a pseudo-single domain structure. The Lisyansky submarine volcano was formed during geomagnetic reversals, as was also the case with the other volcanoes at the Kuril island arc. The volcanic edifice was found to contain supply channels striking nearly vertically, northeast, and northwest, and magma chambers at depths of about 1 km and 2.5‒3 km. The maximum effective magnetization of the Lisyansky submarine volcano is 3.8 A/m.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"418 - 431"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4644309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uranium Sources and Fluid Transport in Volcanic Mineralized Systems: an Example of Streltsovka Caldera, Russia with Reflection on Dornot, Mongolia","authors":"V. A. Petrov,&nbsp;A. A. Pek,&nbsp;V. I. Malkovsky","doi":"10.1134/S0742046322060045","DOIUrl":"10.1134/S0742046322060045","url":null,"abstract":"<p>According to the IAEA classification (<i>Geological Classification</i> …, 2018), uranium deposits of the Streltsovka caldera in the South-Eastern Transbaikalia belong to the volcanogenic (volcanic-related) type based on the characteristics of host rock and/or ore-localizing structure. The implementation of such a descriptive taxonomy in classification of uranium deposits has a long history, but its limitations and the need for transition to models of uranium mineral systems (<i>Descriptive Uranium</i> …, 2020) are becoming increasingly evident. Such a transition for the deposits of the Streltsovka caldera is relevant and logical, bearing in mind a representative example of the space-time relationship of uranium ores in the basement and in the cover of the caldera, which is manifested in the Antei-Streltsovka mineral system (Pek et al., 2020). One of the key points of the mineral-system approach is the reconstruction of the environment of origin and dynamics of system-forming elements interaction in the “source → transport → deposition” sequence. We consider in the article two models of this interaction: (i) the model of forced convection of fluids with a deep-seated magmatic source of uranium and (ii) the model of free thermal convection of fluids with crustal sources of uranium. The hypothesis of thermoconvective circulation of fluids in the residual thermal field of the caldera magma chamber, which is verified by numerical models, substantiates the supply of uranium from three sources of its nearby mobilization: 1) subcaldera chamber, 2) basement rocks, and 3) volcanic rocks filling the caldera. Participation in the ore genesis of the three highly productive uranium sources sheds light upon the origin of the Streltsovka caldera unique ore reserves (~300 000 tU), as compared to the similar in age uranium mineralization of the Dornot ore field (33 000 tU) located about 500 km to the southwest in the territory of Eastern Mongolia (<i>Geological Classification</i> …, 2018).</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"472 - 497"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4931439","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Volcano-Sedimentary and Hydrothermal Bentonite Deposits","authors":"P. E. Belousov,&nbsp;N. D. Karelina","doi":"10.1134/S0742046322060021","DOIUrl":"10.1134/S0742046322060021","url":null,"abstract":"<p>This paper is a study of volcanogenic bentonite. We examine the geological structural settings of the deposits, the paleogeographic environment of sedimentation, structural and textural features of the rocks, and their diagnostic features. We have identified ore-controlling factors in the generation of volcanogenic and hydrothermal bentonite. Comparative analysis has been performed of the original volcanogenic material sampled at deposits in Russia and abroad. The Dash-Salakhly deposit (Republic of Azerbaijan) and a bentonite-bearing province on Sakhalin Island were studied to find how bentonites of different genesis were formed. These studies provide evidence that the composition of the parent material for bentonite varies in a wide range, between basalt and rhyolite. The main factor that controls the generation of bentonite is the type of the sedimentation basin and physicochemical conditions rather than the composition of the parent material.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"451 - 461"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4644304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting the 2015‒2020 Eruptions of Bezymiannyi Volcano, Kamchatka: The Results of a Procedure Based on the SESL'09, Verification of the Parameters","authors":"V. A. Saltykov","doi":"10.1134/S0742046322060069","DOIUrl":"10.1134/S0742046322060069","url":null,"abstract":"<p>In recent decades Bezymianny Volcano, Kamchatka, one of the most threatening volcanic objects of Russia, has produced an average of 1–2 short-lived, but strong, explosive–effusive eruptions per year. The most reliable source of data for identifying a precursory situation before such an eruption seems to be seismicity, with continuous data being supplied by the Kamchatka seismicity monitoring system. The formalized method developed by the present author for predicting Bezymianny eruptions based on a statistical estimation of seismicity level (SESL’09) has performed satisfactorily in real time as well, with the precursory processes before all the eight eruptions of Bezymianny in 2015–2020 being detected. Revision of all characteristics the method involves (efficiency, reliability, and validity) showed that they remained stable when new data were added. The prediction method was supplemented with a new parameter, lead time, which provides a formal procedure to estimate the expectation time for a prediction to come true.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"462 - 471"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4641635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Tephra Discharged by Catastrophic Caldera-Generating Eruptions in the Central Kurils, and the Turbidite of a Large Holocene Submarine Earthquake As Identified in the Core of Glomar Challenger Site 193, Northwest Pacific","authors":"I. V. Melekestsev,&nbsp;O. V. Dirksen","doi":"10.1134/S0742046322050074","DOIUrl":"10.1134/S0742046322050074","url":null,"abstract":"<p>This paper presents results of a specialized analysis applied to deposits reached at site 193 which was drilled during the 19th cruise of the drillship Glomar Challenger in the Pacific Ocean east of the Central Kuril Islands. These data can serve as a basis for the initial phase of future submarine tephrochronologic surveys in the area. Special attention was paid to layers, lenses, and spots of tephra of varying composition and thickness, as well as to sediments having a higher admixture of volcanic glass particles. It was found that at least 8 ashfalls have occurred in the area of site 193, of which 7 took place during the last 115 ka. It is shown that these were more likely related to large and caldera-generating explosive eruptions at volcanic centers in the Kuril Islands. Preliminary dating of these has been carried out. For the first time, a core sample was identified to contain turbidite due to a hypothetical submarine earthquake that occurred in the Early Holocene. We suggest a hypothesis to explain why the sea sediment core samples are disrupted, hypothesizing that thick interbeds of water-rich pyroclastic material of aleuropelite dimension were converted to hydrosols by thixotropy.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"409 - 417"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4643549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epithermal Ag–Au Mineralization in the Kyplatap Volcanic Field, Central Chukotka","authors":"A. G. Pilitsyn,&nbsp;A. V. Volkov,&nbsp;N. E. Savva,&nbsp;A. V. Grigorieva,&nbsp;T. A. Pilitsyna,&nbsp;N. V. Sidorova","doi":"10.1134/S0742046322060057","DOIUrl":"10.1134/S0742046322060057","url":null,"abstract":"<p>This paper discusses mineralogic and geochemical features of dominantly silver mineralization in secondary quartzites of the Kyplatap volcanic field (KVF) confined to the southeastern flank of the eponymous intrusive dome structure (IDS) that complicates the Palyavaam–Pykarvaam volcano-tectonic depression which is part of the Chaun zone of the Central Chukchi sector of the Okhotsk–Chukchi volcanogenic belt (OChVB). The Kyplatap IDS was formed as a large laccolite-like subvolcanic body intruded into the Alkakvun rhyolites and trachyrhyolites. The KVF contains an abundance of secondary quartzites that compose both linear zones along faults mostly northeast striking and fault-bounded isometric fields. Potential ore bodies are represented by linear zones of crushed and brecciated secondary quartzites accompanied by quartz veinlets and veins. The ore bodies are long up to 200 m and 2–5 m thick. Spotty, veinlet-impregnated, and brecciated structures predominate in the ore bodies. The ore mineralization is mostly impregnated, less frequently in veinlets. The main vein minerals are quartz (30–70%), hydromica (15–20%), sericite, kaolinite, adularia, ferrous carbonate, zircon, chlorite, and alunite. The main ore minerals are pyrite, arsenopyrite, acanthite, polybasite, pearceite, and native silver. The typomorphic feature of the mineralization is thin intergrowths of silver sulfosalts, native silver, and iron hydroxides. We note that dominantly silver mineralization in secondary quartzites within the OChVB was found for the first time ever. The results of surveys classify the Kyplatap ore occurrence as a gold-silver mineral type deposit (Au/Ag = 1 : 450 on average) of the selenium subtype because of considerable admixture of selenium in the ore minerals. The occurrence of Ag mineralization in secondary quartzites and mudstones may provide evidence that it belongs to the high-sulfidation epithermal class. These features of the KVF epithermal mineralization are largely similar to the formation of siliceous and quartz–alunite lithocaps that are formed above degassing intrusions. In such conditions, the HS-type ore-bearing fluids are either not formed in the system or did not reach the epithermal depths. The ore field is poorly or moderately eroded, what is indicated by a practically complete absence of minerals of the polymetallic association and by the dominance of acanthite and silver sulfosalts over native phases.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 6","pages":"397 - 408"},"PeriodicalIF":0.7,"publicationDate":"2022-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4644299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Study of Fracture in a Granite Specimen Using Observations of Acoustic Emission","authors":"V. T. Belikov,&nbsp;I. A. Kozlova,&nbsp;D. G. Ryvkin,&nbsp;A. K. Yurkov","doi":"10.1134/S0742046322030010","DOIUrl":"10.1134/S0742046322030010","url":null,"abstract":"<p>Experimental data were interpreted using two amplitude–frequency spectra of acoustic emission as recorded during the application of a uniaxial load to a granite specimen until it fractured. The interpretation procedure was based on the model of disk-shaped cracks. The results enabled us to analyze the variation in structural parameters in the specimen, as well as the fracture process during intervals between the times when the spectra were recorded.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"377 - 384"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4510757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Vp/Vs Kinematic Parameter in the Southern Segment of the Kamchatka Seismic Subduction Zone during the Precursory Period of the March 25, 2020, MW = 7.5 Earthquake and Its Aftershock Process","authors":"M. S. Kuchai,&nbsp;L. B. Slavina","doi":"10.1134/S0742046322050062","DOIUrl":"10.1134/S0742046322050062","url":null,"abstract":"<p>The Vp/Vs kinematic parameter for the Kamchatka seismic subduction zone has been long monitored on a regular basis. This has allowed estimating the behavior of the parameter and revealing its features during the precursory period and actual rupturing of the March 25, 2020 earthquake which occurred in the Pacific plate at the contact between the Pacific plate and the continental slope of Kamchatka. The March 25, 2020 earthquake with its high magnitude (<i>M</i>_L = 7.6, <i>M</i>_W = 7.5) is a rare enough event to occur in the Pacific plate. Knowledge of earth structure in the source region of the earthquake was updated based on the results of deep seismic sounding and continuous seismic profiling which was carried out in the area in the past. It was shown that the earthquake source area is at an inflection in the descending Pacific plate. The source area lies in the layer at the boundary between the asthenosphere and the crust and mantle. The layer is at depths of 30‒60 km and has lower Vp and Vs velocities. The inflection region along Kamchatka shows lower Vp/Vs values, which is a sign of extension along the plate. The source area is in the contact between the Pacific plate, which is subducting under the southern end of Kamchatka, and the North Kuril Islands, as well as the Sea-of-Okhotsk plate. The region shows a distinct change in the anomalous values of the parameter from lower to higher, with the latter being typical for compression. Our study has allowed estimating possible regions of tension and compression in the geological medium.</p>","PeriodicalId":56112,"journal":{"name":"Journal of Volcanology and Seismology","volume":"16 5","pages":"365 - 376"},"PeriodicalIF":0.7,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4514706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}